Specifications

Bulletin No. VVDED397044US R12/00 Section 2—Modbus Plus Overview

December 2000 Peer Cop

Read and Write MSTR Operations

An MSTR write operation transfers data from a controlling device to the

drive controller. An MSTR read operation transfers data from the drive

controller to a controlling device on the network.

Control Block

Table 12 shows the information contained in the top node of the MSTR

control block in a read or write operation.

PEER COP

Peer cop (also known as specific output) is a method of mapping a block

of registers from one specific node to the drive controller’s Command and

Adjustment registers. The transmitting node sends the peer cop data

once per token rotation with the token pass. Each command node can

send up to 32 words of peer cop data to specific nodes on the network as

long as the total does not exceed 500 words.

Peer cop is a fast, efficient way to send data from the command node to

the drive controller. It does not require ladder logic to be written.

NOTE: Peer cop data cannot be passed through bridges. Also, the drive

controller can receive peer cop data but cannot transmit it.

Peer Cop must be enabled through the 8—Communication menu and

configured the same way in MODSOFT

software. The factory setting for

peer cop communication is “No.” To enable peer cop reception:

Table 12: Control Block Registers — Read and Write Operations

Displayed Operation type 1 = Write; 2 = Read

1st implied Error status Displays a hex value indicating MSTR error, when relevant

2nd implied Length

Write = # of registers to be sent to drive controller

Read = # of registers to be read from drive controller

3rd implied

Drive controller

data area

Specifies starting register in the drive controller to be read

from or written to

4th…8th

implied

Routing 1…5

Designates 1st…5th routing path addresses, respectively;

last non-zero byte in routing path is the transaction device.